The runner-up in the Republican race for France's presidency says he is not prepared to be the party's candidate in the election.

Alain Juppe's announcement comes as the man who beat him, Francois Fillon, is under pressure to quit the campaign following claims he paid his wife to do work she did not carry out.

Former prime minister Mr Juppe said the election was being held in "confused" conditions but added: "I confirm for a final time that I will not be a candidate to be president of the republic".

He also criticised Mr Fillon, whose defiance of the justice system and criticism of the media had "led him into a dead-end".

An opinion poll on Sunday found that Mr Juppe would reach the second round if he replaced Mr Fillon.

Mr Fillon has vowed that "no one" could force him to quit his bid for the presidency despite calls for him within his own Republican party to step down.

At a rally in Paris on Sunday - attended by tens of thousands of supporters - Mr Fillon was defiant.

"No one today can prevent me being a candidate," Mr Fillon said in a TV interview on Sunday night in which he again insisted an investigation into the payment scandal was politically motivated.

"Of course it is aimed at stopping me being a candidate," he added.

The Republican party will meet later today to discuss whether to change their candidate for the presidential election.

"I owe you an apology"

At the weekend rally near the Eiffel Tower, Mr Fillon admitted he made mistakes and apologised.

He said: "Even if this charge against me is unjust... I owe you an apology. I made the first mistake, asking my wife to work for me. I should not have done it."

"I made a second mistake by hesitating on how to tell you about it," BFMTV reported the candidate as saying.

Amid chants of "Fillon! President!", he added: "Thank you from the bottom of my heart for being here, you who have braved bad weather conditions, orders, caricatures, sometimes even insults by coming here on this square with such strong symbols."

His supporters put the audience, which is likely to be used as a measure of support for the beleaguered candidate, at 200,000. Independent experts told BFMTV that the area could hold between 35,000 and 50,000 people.

On Saturday, Mr Fillon's British-born wife Penelope broke her silence over the "fake jobs" scandal, saying that she had carried out a "lot of different tasks" for her husband.

The Republicans candidate was the frontrunner until mid-January when the Canard Enchaine newspaper claimed he had paid his wife and two of their children nearly €900,000 as parliamentary assistants or advisers.

Under French law, politicians are allowed to employ family members but investigators are trying to discover evidence of what work Mrs Fillon did carry out.

Opinion polls currently show that far-right leader Marine Le Pen and centrist Emmanuel Macron would go through to the second round of the presidential contest on 7 May, with Mr Fillon eliminated in the first round.

Supporters, including a campaign spokesman and five MEPs from the Republicans party, withdrew their backing this week and called for another candidate to be installed quickly.